My down corn was dryer than the standing corn. Because it died early from lack of moisture on the lighter soils. Stalks had died and dried out then we got a wind and knocked down the dead stuff. The greener stuff that was healthy was still standing and about 6 points wetter than the down stuff.
Now if all your corn was still healthy and just part of it blew down then maybe yes the standing corn may be dryer cause the stalk was still feeding it to maturity. Plus the standing corn would get more air flow to dry it.
So it all depends on the health of the corn before and after the wind.